Hyperkyphosis (HK), or accentuated thoracic spinal curvature, affects as many as 20% to 40% of older adults, making it a serious public health problem. Until recently, most people have assumed that HK affects predominantly older women. Our preliminary research findings demonstrate that older men are at least as likely as older women to suffer from age-related postural changes and that compared with women, men may be at even greater risk of adverse health outcomes such as falls and earlier mortality. In the past 6 years, our research team has made significant contributions towards understanding the epidemiology of HK in older women. We demonstrated that age, vertebral fractures and low bone mineral density only explain a small fraction in the variance of kyphosis progression and that other important factors leading to HK include a family history of HK, early and ongoing height loss, weight loss, and overall vertebral body compression and disc height loss. In addition, by also showing that older women with HK are at increased risk of future fractures, functional decline, and earlier mortality, we have recently established HK as a new female geriatric syndrome. Currently, there are few studies that have investigated HK in men. To begin to address the challenge of better identifying male HK and understanding its epidemiology in terms of pathogenesis and health outcomes, the NIH, through the Director's Bridge Award, has already provided the principal investigator with funding to measure thoracic kyphosis in 1,800 older men from existing baseline and follow-up lateral spine radiographs taken an average of 4.6 years later from the Osteoporotic Fractures in Men (MrOS) Study. MrOS is the first and largest prospective U.S. study devoted primarily to the investigation of osteoporotic fractures in men and it will soon have the gold standard kyphosis measurement available for investigation. All that remains is to obtain the necessary funding to support investigator and analyst time to complete secondary analyses in these older men. With the NIH's investment in obtaining the gold standard kyphosis measurement, this enriched data set confers an unparalled opportunity to: 1) better understand the biological and structural correlates leading to kyphosis progression in older men;2) be able to define the degree of HK that is clinically relevant;and 3) inform strategies on how to prevent its progression. If funded, our research promises to yield important findings that may lead to a paradigm shift in the conceptualization of age-related postural changes in older men. Current clinical practice views male HK as an accepted and little talked about age-related phenomena;a thorough investigation of its biological and structural correlates in men should provide important insights to inform treatment strategies.) PUBLIC HEALTH RELEVANCE: Osteoporosis and hyperkyphosis (commonly known as the dowager's hump) are complex disorders that although related, are distinct entities that until now have been assumed to be the same. While also thought to affect predominantly older women, recent studies demonstrate that hyperkyphosis also commonly affects older men, and that in comparison with women, men with hyperkyphosis may suffer from even worse health consequences. This project will investigate the biological and structural predictors of kyphosis progression assessed over an average of 4.6 years, and determine what degree of kyphosis indicates a pathological condition in a large population of 1,800 older community-dwelling men.